Guide shoe



, yAug. 16, 1966 R. R. TURNER 3,266,577

GUIDE sHoE Filed out. 14, 196s E ig.. 2

RALPH R. TURNER INVENTOR.

United States Patent O 3,266,577 GUIDE SHOE Ralph R. Turner, Calgary, Alberta, Canada, assignor to Pan American Petroleum Corporation, Tulsa, kla., a corporation of Delaware Filed Oct. 14, 1963, Ser. No. 315,911 Claims. (Cl. 16o-222) This invention relates to subsurface well apparatus, and more particularly it relates to guide shoes for attachment to the lower end of con-duit to be run in a well.

When inserting a conduit, such as a casing or liner, in a well drilled into the e-arth, it is customary to place at the lower end of a lcolumn of the conduit a guide shoe to aid in lowering the conduit past minor obstructions on the wall of the well. Typically, a guide sh-oe has a rounded` nose designed to prevent the condu-it from digging into the wall of the hole as it is being lowered into the well bore land it comprises a cylindrical body formed of relatively heavy metal attached to and concentric with the bottom end of the conduit being run. However, in running conduit, particularly in wells where the hole devi-ates from the vertical, there is oftentimes a tendency `for the guide shoe to lodge itself on any existing irregularities or ledges within the well bore. Such difliculties in landing the conduit can be expensive and time consuming, and are to be avoided whenever possible.

A primary object of this invention is an improved guide shoe for running well conduit which enables the conduit to be run more easily and reduces the tendency for it to lodge on irregularities in the wall of the well bore. Other obje-cts of the invention will become more apparent from a reading of the following description taken in connection with the accompanying drawings, illustrating a prefelred embodiment of the invention, wherein:

FIGURE l is illustrative of a vertical crcssJsection-al view of the lower end of a casing string with the guide shoe connecte-d to its lower end; and

FIGURE 2 is a side view of the shoe of FIGURE 1; an-d 'FIGURE 3 is a cross-sectional view of FIGURE 1 taken at line 3-3.

According to the present invention there is provided a guide shoe adapted for attach-ment to a well conduit which comprises a body member for connection to the lower end of a conduit; a nose member connected to said body mem- -ber and extending forwardly thereof, said nose member being eccentric with said body member. -In a preferred embodiment of the invention the nose member is swivelly connected to the body member, and preferably, it is provide-d with circulating iluid ports communicating the interior of the guide shoe with the exterior thereof, said ports being at an angle t-o provide a rotation of the nose when Huid is circulated through the device.

Referring to the drawings, a casing string 1l1, typically is provided nea-r its lower end with a float collar 12, which `may be of the conventional type containing a check valve d0 to unidirectionally control the il-ow of uid in the casing, i.e., to permit a fluid to .pass downwardly through the casing, while preventing the upward ilow of fluid in the casing from below the flo-at collar. Connected to the casing at its lowermost end is guide shoe 13, typically joined to the casing by threads 14. The guide shoe may 'be located directly below the iioat collar, or one or more joints of casing m'ay be connected into the pipe string between the oat collar and the guide shoe.

The guide shoe compri-ses a hollow cylindrical body member 16 at the upper end and la nose member 17 at the lower end. The upper portion of the guide shoe typically -is fabricated of steel or other material providing suitable mechanical properties. The body and the nose may be integral, but it is preferred to fabricate the body and the rice nose of different materials, with the nose being formed of a material which is easily drilled by a drilling bit, such as appropriate aluminum or magnesium alloys, a plast-ic or other such friable m-aterial. The body merely provides a means for coupling the nose to the casing string and for conducting iluid in the casing to the nose. '1`he nose extends forwardly from the body and is rounded at its forward end to enalble the apparatus to move over the rough surface of the well wall more easily when being lowered in the bore hole.

The nose may be joined to the body by a threaded connection or other suitable coupling means for rigidly affixing the nose to the body. However, it .is preferred to rotatably mount the nose on the body so that it is free to swivel about the longitudinal axis. Typically, bearing 18 is provided, such as the bia-ll bearings shown, or other suitable roller bearings or luibricated bearing sur-faces, to reduce the friction between the nose and the body to enable the nose to rotate more easily. Shoulder 19 on the lower end `of the body Vand lshoulder 20 on the upper end of the nose are separated to provide a race for bearing 18. Cover 211 may be provided to seal the bearing so as to exclude particles of rock, dirt or other foreign matter from the bearings. lInner sleeve 22 depends from'upper shoulder 19, p-ast lower shoulder 20 and seals the lbearings in a fluid-tight manner .from fluid and other matter on the inside of the casing. Sealing member 23, such as one or more O-rings or the like kis [fitted lbetween the lower end of sleeve 22 and the inside wall of the nose to elect a duid-tight seal therebetween.

As shown, the body is threaded onto the casing and is mounted coaxially thereon, with the body :being concentric with the casing. The nose piece 17 is swivelly mounted on the body and the vertical center line of the forward end of the elongated hollow nose is offset in one vertical plane with respect to the vertical center line of the body. As shown in FIGUIRE 1, one surface of the no-se is substantially c-o-linear with the body and casing with a relatively sharp curve provid-ed near the forward end, while 'the opposite surf-ace is curved more gradually, with a larger ra-dius of curvature. As shown in FIGURE 2, the other two sides taper substantially evenly from the diameter of the body to the smal-ler diameter front end of the nose. Thus, the forward end of the nose is eccentric with respect to the body and there is provided a greater guiding surface area on one lside of the nose than on the other. A plurality of circulating ports 24 are provided in the wall of the nose so that a fluid may be passed downwar-dly through the casing and the shoe outwardly into the well bore. Preferably, the ports 24 are formed in the wall of the nose near its lower end and are offset, or at an angle to the tangent o-f the wall of the nose. As fluid is pumped under pressure down the casing, it passes through the ports tangentially to the nose and imparts a rotating or whirling motion to the nose so that the nose tends to turn with respect to the body and the casing. Of course, the .rotational velo-city of the nose will depend upon the velocity o-f fluid passed through the ports. Thus, as the casing with the guide shoe `at its bottom end is lowered downwardly into the well bore, the rotational tendency produced by passing fluid through the device enables the nose to turn so as to allow the greater guiding area on one surface of the nose to be adjacent to the well bore and to enable it to contact the same, so as to follow, for example, any lateral deviation in the well bore or to move past minor obstructions or irregularities in the wall of the well.

Shear pins 26 positioned in holes forme-d in the wall of body 16 and in shoulder 19 may be employed to join the nose to the body so that in the event the circulating ports become plugged, or it is otherwise desirable to detach the lshoe from the rest of the pipe string, the pins may be sheared by applying sucient yweight to the shoe. Various other suitable means may be employed to releasably join the s-hoe to the casing string.

From the foregoing description it is apparent that the present invention provides an improved guide shoe which enables a conduit to be more easily run in a well, and especially in a Well wherein a deviation from the vert-ical occurs. The above descrip-tion of a preferred embodiment of the invention is given for the purpose of illustration and is not intended to limit the scope of the invention.

-I claim:

1. A guide shoe for attachment to a.well conduit which compri-ses a body member adapted to lbe connected to the lower end of said conduit; a tapered nose member swive'lly attached to said body member and extending forwardly -thereof, the forward end of said nose member being ec- 4centric with respect to said body member; and a plurality of ycirculating ports in said nose member placing the interior of said nose member in ow communication with the exterior thereof, said circulating ports being positioned tangentially with respect to the wall of said nose member to impart a rotary motion the-reto when a fluid is passed downwardly through said shoe.

2. A guide shoe als deifned in claim `1 in which said nose member is releasably attached to said body member.

3. An apparatus as defined in claim 2 in which said nose member is made of an easily dril'lalble material.

4. A guide shoe for attachment to a well conduit which compri-ses: a body member adapted to be connected to t-he lower end of said conduit; a nose member whose forward end is eccentric with respect to said body member, all o-f the exterior surface including t-he apex of said nose member being convex; means rotatably attaching said nose member an-d said body member; and a plurality of circulating ports in said nose member placing the interior of said nose member in fluid communication with the exterior thereof.

5. A guide shoe as defined in claim 4 in which said circulating ports are positioned tangentially with respect to the wall oi' said nose member to imp-art a rotary mct-ion thereto when a fluid is pas-sed downwardly through said shoe.

References Cited by the Examiner UNITED STATES PATENTS '1,715,767 6/1929 Le -Flore 166-22'3 1,830,851l 11/1931 Mlurphy 166-225 2,783,972 3/1957l Pohlmann 175-422 CHARLES E. OCONNELL, Primary Examiner.

o J. A. LEPP'INK, Assistant Examiner. 

1. A GUIDE SHOE FOR ATTACHMENT TO A WELL CONDUIT WHICH COMPRISES A BODY MEMBER ADAPTED TO BE CONNECTED TO THE LOWER END OF SAID CONDUIT; A TAPERED NOSE MEMBER SWIVELLY ATTACHED TO SAID BODY MEMBER AND EXTENDING FORWARDLY THEREOF, THE FORWARD END OF SAID NOSE MEMBER BEING ECCENTRIC WITH RESPECT TO SAID BODY MEMBER; AND A PLURALITY OF CIRCULATING PORTS IN SAID NOSE MEMBER PLACING THE INTERIOR OF SAID NOSE MEMBER IN FLOW COMMUNICATION WITH THE EXTERIOR THEREOF, SAID CIRCULATING PORTS POSITIONED TANGENTIALLY WITH RESPECT TO THE WALL OF SAID NOSE MEMBER TO IMPART A ROTARY MOTION THERETO WHEN A FLUID IS PASSED DOWNWARDLY THROUGH SAID SHOE. 